The execution of an electrodeposition process with stability to gain satisfactory results requires a proper monitoring of the composition of an electrolyte furnishing the depositing metal. In an electroforming operation, a large amount of metal is deposited and the electrolyte tends to alter the concentration quickly. It is desired to inspect the composition and to replenish the consumed metal in the electrolyte. The common practice effects replenishment by adding a corresponding metal salt to the solution tending to be depleted of the depositing metal upon inspection from time to time. This procedure has been found to give rise to problems because of possible introduction of impurities which may hinder or even be detrimental to satisfactory metal deposition.